Hi Tgger, thought I'd reply on here.
Unfortunately I got a lot of the reading books we use, via ebay, from a lady who was a retiring tutor and they are probably out of print.
With ds1 we went up to songbirds level 6. We also read the "red nose readers" series, red/yellow/blue levels for increasing difficulty (written by Allan Ahlberg) so very silly and great fun for kids. I also used a set of 12 Usborne phonics readers "Mouse moves House, Hens Pens, etc (The Book People again) and the Apple Tree Farm series of 20 books. (The Book People again)
We read a Thomas the Tank Engine series which said it was for ages 3-5 but I'd put it at age 5-6. Each book got progressively harder and it told you in the back of each book which one to progress to next.
We also read some Collins books, in particular I think "skyways" with a series about a boy in medieval times wanting to train as a knight.
Don't overlook good old Dr Seuss and cat in the hat type readers (graded by colour on the back cover) there are so many different ones of these and you can get quite a lot for your money on ebay.
Peter & Jane from the 60's and 70's, these are look and say but by the time your child has mastered songbirds level 6 they'll probably use phonics wherever they can and work out the rest with assistance.